Annual U.S. Greenhouse Gas Inventory

The Annual U.S. Greenhouse Gas (GHG) Inventory is a report that provides information on the sources and sinks of greenhouse gases in the U.S. The newest version was published on April 11, 2024 and compiles the GHG data from 1990 to 2022. The report is produced by the U.S. Environmental Protection Agency (U.S. EPA) and is used to inform policy decisions related to climate change.

What are the Key Findings from the Report?

The report includes emissions of carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and fluorinated gases, with CO₂ accounting for the majority of U.S. greenhouse gas emissions. The report found that in 2022, greenhouse gas emissions in the United States were 6.34 billion metric tons of carbon dioxide equivalent (CO₂e), a slight increase from 2021 but a 3% decrease since 1990. Net CO₂e emissions have decreased by 15% from 2005 levels, which is consistent with the overall downward trend. The sectors with the largest decrease are the energy and waste sectors. Figure 1 shows the U.S. GHG emissions trends from 1990 to 2022 (U.S. EPA Document No. 430-R-24-004).

Figure 1
U.S. Greenhouse Gas Emissions and Sinks by Gas.

The 2022 data shows that carbon dioxide emissions from natural gas combustion have been increasing over the years while coal and petroleum usage have been slowly decreasing. Coal combustion had an increase in 2021 but is trending down again with a 6% decrease from 2021. The rise in natural gas combustion emissions was seen across all sectors except in the U.S. Territories sector. The trends in CO₂e emissions from fossil fuel combustion are subject to various long-term and short-term factors. Yearly fluctuations are often tied to changes in economic conditions, energy prices, weather, and the availability of non-fossil fuel alternatives. For instance, a year marked by high consumption, low fuel prices, and extreme weather events is likely to see increased fossil fuel use compared to a year with an economic downturn, high fuel prices, and mild weather. The trends from 2021 to 2022 show the continuing effects of the COVID-19 pandemic, which initially decreased fossil fuel demand in 2020 but led to an increase as activities resumed in 2022. However, more permanent shifts in energy usage patterns are influenced by broader societal trends such as population growth, the number of vehicles, house sizes, and the efficiency of energy-consuming equipment. Social planning and consumer behavior, like choosing to walk, bike, or telecommute, also play a significant role in these long-term changes.

The Land Use, Land-Use Change, and Forestry (LULUCF) sector offset 13.5% of total emissions in 2022. These activities include reducing deforestation and ecosystem restoration, which help in carbon sequestration. An important driver in improving the LULUCF sector is forest management practices.

The report also provides information on the sources and sinks of specific greenhouse gases, with transportation, electricity generation, and industrial activities being the three largest sources. Transportation accounts for the largest portion of GHG emissions at 28.4% with the lowest sector being residential emissions. The full trends for GHG emissions by sector are shown in Figure 2 (U.S. EPA Document No. 430-R-24-004). The transportation and electric power industry sectors saw a dip in emissions in 2020 due to the COVID-19 pandemic and 2021 and 2022 emissions reflect the economic rebound.

Figure 2
U.S. Greenhouse Gas Emissions Allocated to Economic Sectors

Since 1990, the United States has seen a marginal decline in greenhouse gas emissions, averaging a 0.01% annual decrease. GHG emissions peaked in 2005 and have been consistently declining since. The rate of decline in emissions has been slightly slower compared to the growth in total energy usage, fossil fuel consumption, as well as the overall growth of the nation’s gross domestic product (GDP) and population, shown in Figure 3 (U.S. EPA Document No. 430-R-24-004). This trend is due to the increase in energy efficiency technologies and GHG emissions reduction strategies.

Figure 3
U.S. Greenhouse Gas Emissions Per Capita and GDP

What is the Direction for the Future?

The U.S. GHG Inventory offers valuable information for decision-makers as they deal with climate change. The report highlights the need to reduce GHG emissions from the transportation and industrial sectors, which are the largest contributors to GHG emissions. There is potential for more carbon regulations to reduce the GHG emissions associated with these sectors. It also demonstrates that economic growth and GHG emissions reductions can be achieved simultaneously.

Strategies the U.S. can promote to reduce GHG emissions include transitioning to clean energy sources, promoting energy efficiency, and supporting the development of low-emissions transportation options. Recently these strategies have been promoted through the Inflation Reduction Act (IRA) and the Advanced Energy Project Credit (48C) Program.

Conclusions

The Annual U.S. Greenhouse Gas Inventory reveals the sectors that are the largest sources of GHG emissions in the country. Overall, GHG emissions increased from 1990 to 2000 then plateaued until the decline starting in 2008. There has been a decrease in GHG since the peak in 2005 but it is not at the necessary rate to mitigate the largest impact of climate change, according to the Intergovernmental Panel on Climate Change (IPCC). Although there has been success in lowering emissions, there is still a lot of effort needed to meet the economy-wide net-zero by 2050 objective set by the IPCC.

If you have questions about how to interpret this report or would like to discuss how your company contributes to GHG emissions, we would be glad to talk with you. Please contact Louise Shaffer at lshaffer@all4inc.com or your ALL4 Project Manager to discuss how we can help develop or improve your corporate GHG inventory or develop a strategy to reduce your GHG footprint.